The center for Demography and ecology at the University of Wisconsin, Madison, was formed in 1962 to facilitate research and training in population studies. The Center is a cooperative effort of faculty specializing in population-related research who combine and coordinate resources, facilities, and personnel. Funding is provided by this Population Center grant from the NICHHD Center for Population Research, by a core grant from the Hewlett Foundation, by a training grant from NICHHD, by research grants and contracts from NSF, NIH, and other agencies, and by the University. This population Center grant funds core facilities and services rather than specific research projects. Core facilities include an interactive computer dedicated to demographic data processing and extensive data and print libraries. Core services include general-purpose systems and applications programming, and administrative services. Many specific research projects are carried out at the Center by 26 affiliated faculty, 10 postdoctoral researchers, and about 35 graduate students. Most of the recent and continuing research projects may be grouped into four main categories: (1) Demography of the life cycle; (2) Spatial distribution; (3) Demographic methodology; (4) Social problems and policy.